Method for mounting a bearing or other device and tapered adapter onto a shaft

ABSTRACT

An assembly and method is provided for properly securing a device such as a bearing, pulley, sheave or the like to a shaft wherein a split tapered adapter is received about the shaft, the adapter having a first end of lesser diameter, a second end of greater diameter, and a tapered surface therebetween, and threads defined about the first end of the adapter, a locknut is in threaded engagement with the first end of the adapter and a device received about the adapter. The locknut has a set of set screws carried therethrough and spaced therearound which are controlled such that the force developed thereby is adequate to clamp the adapter to the shaft and seat the device on the adapter yet is inadequate to move the device toward the second end of the adatper. A second plurality of set screws may be received through said locknut which generate adequate force to move the device up the adapter to achieve a predetermined location of the device. Alternately, the locknut may be turned a predetermined member of degrees of rotation to force the device up the adapter by a predetermined amount.

This is a division, of application Ser. No. 07/491,300, filed Mar. 9,1990, now U.S. Pat. No. 5,011,306.

BACKGROUND OF THE INVENTION

The present invention relates to the use of tapered adapters for fittingbearings, pulleys, sheaves and the like to shafts and more particularlyto an improved method and apparatus for properly seating an adapter anda device to a shaft and to moving the device up the adapter to acquire aproper location of the device on the adapter. While other devices arecontemplated, the specification is specifically directed to bearinginstallation only.

It is well known in the art to employ split tapered adapters to properlysecure bearings to shafts. Generally, a nut is provided to first seatthe bearing and adapter with a plurality of screws to urge the taperedsurfaces of the adapter and the inner race of the bearing togetherthereby properly positioning the two and causing the adapter to contractand grip the surface of the shaft. It is thus well known to use setscrews in the locknut to assist in moving the bearing up the adapter.Examples of such assemblies are found in U.S. Pat. No. 3,325,175 toLower, U.S. Pat. No. 3,497,274 to Yardley and Dodge Engineering Catalog,Vol. 1, pp. B4-24, 25 (Adapter Mounted SAF-SAFS-SDAF Spherical RollerBearings).

In order, however, to properly secure the bearing by such method it isnecessary to first properly seat the adapter to the shaft and thebearing to the adapter. Then the bearing is "snugged up" to the adapter,expanding the inner race of the bearing and providing a tight fit with aholding power approximating that of a conventional press or interferencefit. However, it is difficult for an installer to accurately judgewhether or not the elements are all properly seated, and that thebearing expansion is correct. If the installer's judgment is wrong, theamount of expansion of the inner race will not be proper which can leadto a loose bearing fit or excessive expansion, both of which willultimately lead to bearing failure.

The apparatus and method according to the present invention remove theneed for a judgment on the part of an installer and permit consistentknown accuracy in installation to achieve both a proper seat and aproper bearing expansion, or location of another device. No known priorart is believed to teach or suggest the present invention.

SUMMARY OF THE INVENTION

The present invention recognizes and addresses the foregoingdisadvantages, and others, of prior art bearing assemblies.

Accordingly, it is an object of the present invention to provide abearing assembly which removes the need for judgment on the part of theinstaller in installing the assembly.

It is another object of the present invention to provide an improvedadapter assembly for proper seating of the adapter and a bearing,pulley, sheave or the like on a shaft.

It is a further object of the present invention to provide a means forproperly securing a bearing to a shaft with a tapered adapter andproperly expanding the bearing.

Yet another object of the present invention is to provide a method forinstalling a bearing on a shaft using a tapered adapter withoutrequiring judgment as to the point at which all elements are properlyseated and ready for tightening.

It is still another object of the present invention to provide animproved locknut for use with a tapered adapter for securement of abearing, pulley, sheave or the like to a shaft.

It is still a further object of the present invention to provide amethod for securing a bearing about a tapered adapter and clamping theadapter to a shaft while properly expanding the bearing about theadapter.

These as well as other objects are achieved by the steps of locating atapered adapter about a shaft, the adapter having a first end of lesserouter diameter, a second end of greater outer diameter, a taperedsurface between the two ends, threads defined about the first end, andsaid adapter defining a split through its length; loosely fitting abearing or other device to be mounted about the adapter, threading alocknut onto the first end of the adapter to abut the bearing or otherdevice with the locknut having a set of set screws spacedcircumferentially thereabout and generally parallel to said shaft, theset screws being controlled such that the force developed thereby isadequate only to clamp the adapter to the shaft and seat the bearing orother device on the adapter, while being inadequate to move the bearingor other device toward the second, large end of the adapter; tighteningthe set screws to clamp the adapter to the shaft and seat the bearing orother device and adapter on the shaft; moving the bearing or otherdevice a known, predetermined distance up the tapered surface toward thesecond end of the adapter to achieve a known positioning of same andsecuring the bearing or device in place.

In a most preferred embodiment, the locknut has two sets of set screwsor other threaded elements therearound. A first, set is sized to onlyseat the bearing and adapter on the shaft, generally up to a maximumpoint short of where the longitudinal split in the adapter becomesclosed. A second set of set screws or other threaded elements is locatedaround the circumference of the locknut, interspaced with the first setof set screws, and the set screws are sized to develop adequate forceagainst the bearing or device to force same up the taper or incline ofthe adapter and thus position the bearing or device as desired.

With a known distance of bearing movement, for example, achieving aknown expansion for a particular bearing, the distance between the faceof the locknut and the bearing can be measured. The second set of setscrews may then be employed to force the bearing onto the adapter by ameasured, known amount to achieve proper expansion of the bearing. Afterproper movement of the bearing by the second set screws, the set screwscan be backed out and the locknut threadably moved into contact with thebearing to lock the assembly in place.

In other embodiments, different means can be employed in the step ofmovement of the bearing, for example, once the bearing and adapter havebecome known to be seated onto the shaft. For example, once seated, thesmaller, seating set screws can be moved out of contact with thebearing. Thereafter, using a known degree of rotational turn of thelocknut to impart a known amount of bearing movement, the locknut can bebrought into contact with the bearing and then turned a predeterminednumber of degrees to achieve proper expansion of the bearing. Once, ofcourse, the desired movement and attendant expansion have been realizedby turning of the locknut, the assembly is automatically locked by thelocknut.

The bearing assembly according to the present invention comprises abearing for receipt on a tapered adapter, said bearing including aninner race defining a central bore through said bearing, an outer raceand a plurality of bearing elements located between said inner and outerraces; a split tapered adapter, said adapter defining a boretherethrough for receipt of a shaft therein, said adapter having threadstherearound for a portion of the length of same; and a locknut receivedaround said adapter at said threaded portion and in threaded connectiontherewith, said locknut defining a plurality of threaded openingstherearound generally parallel to said bore through said adapter, andthreaded elements in threaded connection with said threaded openings insaid locknut, said elements being of a size to move said bearing ontosaid adapter only for seating said bearing and said adapter on a shaftwhile being inadequate in size to further move said bearing onto saidadapter for expansion of said bearing.

More specifically, the threaded elements located on said locknut forseating said bearing and said adapter tightly about said shaft arepreferably small set screws, but in any event collectively developinadequate force to move the bearing onto said adapter further thanrequired to close the split adequate to seat the adapter on the shaft.Hence, full use of the small set screws terminates at initial seating ofthe bearing and adapter on the shaft.

Consequently, one installing a bearing assembly according to the presentinvention need not make any judgment as to whether the bearing andadapter are tightly seated on the shaft. Such point is reached at theend of movement of the bearing by the set screws.

In a further form, the present invention includes a tapered adapterassembly for the mounting of a bearing on a shaft, said assemblycomprising an annular split element, said element defining a boretherethrough of common diameter, said element having an outer surfacethat tapers from a first diameter section upwardly to a second, largerdiameter section for receipt within a bore defined by a bearing or otherdevice to be mounted, said bore having a reverse taper to the outersurface of said annular split element, said first diameter section ofsaid element defining threads therearound; and a locknut received aroundsaid first diameter section in threaded engagement therewith, saidlocknut defining a plurality of threaded openings located therearound,said threaded openings being generally parallel to a shaft about whichsaid adapter assembly is to be mounted; and members received in threadedconnection with said plurality of openings, said threaded members beingcapable collectively of generating a force when threadedly moved againsta bearing or device received about said adapter adequate only to seatsaid bearing or device and said adapter on said shaft while beinginadequate to move said bearing up said tapered surface of said adapter.In a preferred arrangement, said locknut defines a further plurality oflarger openings therearound with larger threaded members therein whichwill generate force adequate to move said bearing or other device upsaid tapered surface of said adapter.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, to one of ordinary skill in the art, is set forthmore particularly in the remainder of the specification, includingreference to the accompanying figures in which:

FIG. 1 is a perspective view assembly in accordance with the presentinvention;

FIG. 2 is a partial vertical cross-sectional schematic view of a bearingassembly according to the present invention as loosely received about ashaft;

FIG. 3 is a partial vertical cross-sectional schematic view of a bearingassembly as illustrated in FIG. 2 with all elements seated on the shaft;

FIG. 4 is partial vertical cross-sectional schematic view of a bearingassembly as illustrated in FIG. 2 showing a preferred technique formoving the bearing up the tapered adapter;

FIG. 5 is a partial vertical cross-sectional schematic view of a bearingassembly as illustrated in FIG. 4 with the bearing moved up the adapterand locked in place;

FIG. 6 is a partial end view of an adapter assembly according to thepresent invention illustrating a preferred embodiment; and

FIG. 6-A is a cross-sectional view of a portion of the locknut of FIG. 6as taken along a line 6--6, and illustrating a further embodiment ofsame.

Repeat use of reference characters in the present specification anddrawings is intended to represent same or analogous features or elementsof the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Making reference to the Figures, preferred embodiments of the presentinvention will be described in detail. In FIG. 1, a bearing assemblygenerally 10 is illustrated in accordance with the present invention.

Bearing assembly 10 includes a bearing unit 12, a tapered adapter 20 anda locknut 34 which are employed to mount an assembly on a shaft (notshown). Bearing 12 is a spherical roller bearing which has an outer race14, an inner race 16 and a plurality of roller bearings 18. Taperedadapter 20 is shown with threads 22 disposed about an end 24 thereof ofa first, small diameter. As better shown in FIGS. 2-5, tapered adapter20 has one end 24 of a small or lesser diameter and an opposite end 126of greater diameter with an exterior tapered surface 128 extendingtherebetween. Generally, inner race 16 of bearing 12 is received ontapered surface 28 of adapter 20 and has a complementary inner surface(see FIGS. 2-5). Adapter 20 defines a split 30 therethrough whichextends along the length thereof. Split 30 allows adapter 20 to befreely moved onto a shaft carried through an inner bore 32 of adapter 20and be securely clamped thereon.

Locknut 34 is threadably receivable on threaded end 24 of adapter 20. Inaccordance with the present invention, locknut 34 defines a plurality ofthreaded openings 35 which receive threaded elements 36 therein, such asset screws. Openings 35 are spaced circumferentially around locknut 34.Set screws 36 are limited in size and/or number such that the forceexerted thereby is sufficient to clamp adapter 20 to a shaft carried ininner bore 32 up to a maximum point just before split 30 becomes closedabout the shaft. The force developed by set screws 36 is, however,inadequate to move bearing 12 up tapered surface 28 of adapter 20, aswill be discussed further below.

With the bearing assembly 10 described above, the adapter 20 and bearing12 may be placed onto a shaft, located as desired and secured to theshaft by turning set screws 36 to cause adapter split 30 to closeadequately for adapter 20 to securely grip the shaft. One using thistechnique will thus know when assembly 10 is secured or seated to shaft10. Thereafter bearing 12 can be forcably moved up tapered surface 28 ofadapter 12 by a predetermined amount to achieve a known, and correctexpansion of bearing 12 (of inner race 16). FIGS. 2-5 schematicallyillustrate a technique for the overall mounting technique whichconsistently yields a correct bearing mounting.

Referring now to FIGS. 2 and 3, a bearing assembly generally 110 isshown loosely mounted "finger tight" about a shaft 111. Thus, inaccordance with the present invention, a tapered adapter generally 120having a first end 124 and a second end 126 with threads 122 definedabout the first end has been located loosely about shaft 111. Clearancespace 121 is illustrated in FIG. 2 to represent that the adapter is notyet tightly clamped to the shaft. Bearing 112 is loosely fit about alower end of adapter 120 and locknut 134 having set screws 136 isthreadedly received on first end 124 of adapter 120. It is to beunderstood that there may be any number of screws 136 so long as theyare controlled in size and/or number such that the force developedthereby is adequate to clamp adapter 120 to shaft 111 and to seatbearing 112 on the adapter yet is inadequate to move the bearing towardthe second, larger end 126 of the adapter. FIG. 3 illustrates the properseating of the elements as attained by the force exerted by set screws136. Note that the clearance space 121 of FIG. 2 has been taken up.

After the elements have been properly seated, bearing 112 is to beforced a predetermined distance up the tapered surface 128 toward secondend 126 of adapter 120 for proper mounting to the shaft, after whichassembly 110 is secured in place.

Referring to FIG. 4 and FIG. 6, a preferred apparatus is illustratedwhich includes means for specific movement of bearing 112 up taperedsurface 128 of adapter 120. Locknut 134 is shown in end view in FIG. 6and includes small set screws or other threaded members 136 as discussedabove. Also around the circumference of locknut 134 a plurality oflarger threaded openings 137 are defined in which are received largerset screws or other threaded elements 138. Larger set screws 138 arecapable of developing a force when turned to move bearing 112 up taperedsurface 128 of adapter 120.

With the bearing assembly initially set by small set screws 136, one canmeasure the distance D between a face 134' of locknut 134 and anadjacent face 112' of bearing 112 (see FIG. 3). Knowing the properdegree of expansion for the inner ring (race) of bearing 112 that isnecessary for a 2222 OK bearing, e.g. 0.002 inch, and the taper oftapered surface 128 of adapter 120, e.g. 12:1 one knows that bearing 112should be moved up the tapered surface 0.024 inch (12×0.002). Large setscrews 138 can thus be turned to achieve a movement of bearing toenlarge the dimension D by 0.024 inch to accurately expand bearing 112by 0.002 inch. For proper movement, large set screws 138 should beturned in small increments in sequence around locknut 134.

Following movement of bearing 112 the proper distance up adapter 120,set screws 138 may be turned in an opposite direction to be moved out ofthe way and locknut 134 then tighteded into contact with face 112' ofbearing 112 to lock assembly 110 in place.

While the various sizes of set screws to be employed may vary with thesize of the bearing, the taper of the adapter, the size of the shaft andthe like, the force developed by the first, and normally small setscrews, should be no more than that necessary to close split 130 ofadapter 120 adequate for securement of bearing 112 onto adapter 120 andadaptor 120 onto the shaft, e.g. to a point where there is no clearancebetween the components. By way of example, for a conventional 22234Kbearing and an S34-515 adapter having a 12:1 taper, the small set screwsmay be 3/8 inch, while the large set screws may be 7/16 inch or larger.Determination of other sizes for other bearing-adapter assemblies shouldbe readily determinable by one skilled in the art without undueexperimentation.

In the broadest context of the method according to the presentinvention, all of the set screws threadedly engaged with a locknut couldbe the same size with only certain of the set screws being employed toseat the adapter, after which the remainder or all of the set screwscould be employed to move the bearing up the adapter. Likewise, thefirst set of set screws could be large (though few in number) and thesecond set for moving the bearing could be smaller than the first andused in a large enough number to generate the required force.

A further embodiment of the present invention for moving bearing 112 upadapter 120 may be seen in FIG. 6-A. A portion of a locknut 234 isillustrated having a pin 240 received therethrough under the bias of aspring 242. With the bearing assembly 110 initially mounted on theshaft, locknut 234 is brought into contact with surface 212' of bearing212 which would force pin 240 into locknut 134 against the bias ofspring 242. Then turning large set screws 138, as bearing 212 moves upthe adapter, pin 240 is moved out of locknut 234 by the bias of spring242. Graduated indicia 244 on pin 240 can be read to determine theamount of bearing movement achieved.

In a further embodiment, when locknut 134 is in contact with bearingsurface 212', pin 240 would protrude from an opposite face of locknut134 by an amount equivalent to the desired amount of movement of bearing212 up the adapter. Thereafter bearing 212 is moved away from locknut134 by some means until an outer tip 241 of pin 240 returns due to thespring bias to a position flush with said opposite face of locknut 134,at which point bearing 212 will have been moved the correct,predetermined amount.

In yet a further embodiment for moving a bearing up the adapter toachieve the desired expansion of the bearing, reference is again made toFIG. 6. Indicia 139 on locknut 134 of FIG. 6 are indicative of degreesof rotation when referenced to a line 13 on bearing 112. Zero degrees isillustrated in alignment with reference line 113 on surface 112' bearing112. Once the assembly is initially seated on the shaft, locknut 134 canbe tightened into contact with bearing 112. Then locknut 134 can beturned a predetermined number of degrees to move the bearing apredetermined distance up the adapter. For example, assuming again ataper of 12:1 for the adapter and a need to expand the inner ring of thebearing by 0.002 inch. If the locknut has 12 threads per inch, the nutadvances 0.0833 inch per turn of the nut. Accordingly, 0.288 turn wouldbe required to achieve a bearing movement of 0.024 inch which equates to103.7 degrees. Hence, by using the degree indicia 139 on locknut 134 andmark 113 on bearing surface 112' , one could turn locknut 103.7 degreesand know that proper bearing expansion had been achieved. Since locknut134 would then still be in contact with bearing 112, assembly 110 wouldbe automatically locked on the shaft.

While a particular bearing structure-adapter assembly has beenillustrated and described herein, obviously other types of bearings andtapered adapters may be employed according to the present invention.Moreover, any of the embodiments shown in any of the figures may be usedwith any other embodiment shown or contemplated hereby, whether inaddition to other features or in lieu thereof. Also the adapter andlocknut according to the present invention could be employed formounting other devices on a shaft such as for example pulleys, sheaves,and the like.

These and other modifications and variations to the present inventionmay be practiced by those of ordinary skill in the art, withoutdeparting from the spirit and scope of the present invention, which ismore particularly set forth in the appended claims. Furthermore, thoseof ordinary skill in the art will appreciate that the foregoingdescription is by way of example only, and is not intended to belimitative of the invention so further described in such appendedclaims.

What is claimed is:
 1. A method for securing a device to a shaft,comprising:locating a tapered adapter about said shaft, said adapterhaving a first end of a first diameter, a second end of second largerdiameter, a tapered surface therebetween and threads defined about saidfirst end, said adapter defining a split therethrough along the lengththereof; loosely fitting a device about said adapter; threading alocknut located on said first end of said adapter to abut said device,said locknut having a plurality of threaded elements carriedtherethrough in threaded relationship therewith and spacedcircumferentially thereabout, said threaded elements being dimensionedsuch that upon turning same, the force developed thereby is adequate toclamp the adapter to the shaft and seat the device on the adapter whilebeing inadequate to move the device further toward the second end of theadapter; turning said threaded elements to move said device up thetapered adapter a sufficient distance to seat said adapter and device tosaid shaft; thereafter moving said locknut to force said device apredetermined distance up the tapered surface of said adapter towardsaid second end of same; and securing the device in place.
 2. A methodset forth in claim 1 wherein the step of moving said locknut to forcethe device up the tapered surface of said adapter toward the second endof same is achieved by backing out said threaded elements, tighteningthe locknut to abut said device, and thereafter advancing the locknut apredetermined number of degrees of rotation.
 3. A method is defined inclaim 1 wherein said locknut has a second plurality of threaded elementsin threaded connection therewith and wherein the step of moving saidlocknut to force said device up the tapered surface of said adapter isachieved by turning said second plurality of threaded elements againstsaid device until said device has been moved by said predetermineddistance.
 4. A method as defined in claim 1 wherein after movement ofsaid device up said adapter, said device is secured in place by movingsaid locknut into contact therewith.
 5. A method for securing a bearingto a shaft comprising the steps of:locating a split tapered adapter onsaid shaft with a bearing received therearound, said adapter having afirst end of a lesser diameter and a second end of a greater diameterand a tapered outer surface extending therebetween, at least a portionof said first end defining threads therearound and having a locknut inthreaded engagement therewith, said locknut defining a plurality ofthreaded openings therethrough in a direction parallel to said adapterand having first threaded elements in threaded engagement therewith,said first threaded elements being capable of developing a force uponturning adequate only to seat said adapter on a shaft passingtherethrough, said locknut further defining a plurality of secondthreaded openings therearound in a direction generally parallel to saidadapter and having second threaded elements in threaded engagementtherewith, said second threaded elements being capable upon turning ofexerting a force adequate to move said bearing up said tapered surfaceof said adapter; tightening said locknut until said locknut engages saidbearing; turning said first threaded elements until said adapter andsaid bearing are seated on said shaft; thereafter turning said secondthreaded elements adequate to move said bearing up said tapered adapterby a predetermined amount; and thereafter backing out said threadedelements and tightening said locking against said bearing.
 6. A methodof securing a bearing to a shaft as defined in claim 5 wherein saidfirst and second threaded elements are set screws.
 7. A method ofsecuring a bearing to a shaft as defined in claim 6 wherein said secondset screws are larger than said first set screws.
 8. A method as definedin claim 5 wherein said second threaded elements are interspaced amongsaid first threaded elements. PG,21
 9. A method for securing a device toa shaft, comprising:locating a tapered adapter about said shaft, saidadapter having a first end of a first diameter, a second end of secondlarger diameter, a tapered surface therebetween and threads definedabout said first end, said adapter defining a split therethrough alongthe length thereof; loosely fitting a device about said adapter;threading a first means on said first end of said adapter to abut saiddevice, said first means having a plurality of threaded elements carriedtherethrough in threaded relationship therewith and spacedcircumferentially thereabout, said threaded elements being dimensionedsuch that upon turning same, the force developed thereby is adequate toclamp the adapter to the shaft and seat the device on the adapter whilebeing inadequate to move the device further toward the second end of theadapter; turning said threaded elements to move said device up thetapered adapter a sufficient distance to seat said adapter and device tosaid shaft; thereafter moving said first means to force said device apredetermined distance up the tapered surface of said adapter towardsaid second end of same; and securing the device in place.
 10. Themethod set forth in claim 9 above wherein the step of moving said firstmeans to force the device up the tapered surface of said adapter towardthe second end of same is achieved by backing out said threadedelements, tightening said first means to abut said device, andthereafter advancing said first means a predetermined number of degreesof rotation.
 11. A method as defined in claim 9 wherein said first meanshas a second plurality of threaded elements in threaded connectiontherewith and wherein the step of moving said first means to force saiddevice up the tapered surface of said adapter is achieved by turningsaid second plurality of threaded elements against said device untilsaid device has been moved by said predetermined distance.
 12. A methodas defined in claim 9 wherein after movement of said device up saidadapter, said device is secured in place by moving said first means intocontact therewith.